CASECASE

CASE05

Glass run channels (GRC)

Mitsui Chemicals proposes the sliding modification solution of co-extruding on to GRCs.

Characteristics of using LUBMER^™ for glass run channels

Abrasion resistance, sliding properties, improvements to process and work environment

Examples of use and evaluation

Automotive glass run channels

Issues with current materials in the area of glass run channels

A glass run channel is a material installed between a vehicle's window glass and the window frame. It needs to make it simple to perform the up and down, opening and closing operations of the window while also forming a seal between the window glass and frame. While vulcanized rubbers such as EPDM are used for glass run channels, when used alone this material sometimes lacks sufficient sliding properties, and to deal with this the surface layer may have a sliding coating applied, be flocked, or otherwise treated. However, as these measures increase the number of work processes involved and carry the risk of generating harmful substances, in some fields there are calls for change in consideration of the SDGs.

Solution

LUBMER^™ from Mitsui Chemicals is an extrusion-moldable pellet type ultra-high molecular weight polyethylene. With LUBMER^™, a regular extrusion molding machine can be used to co-extrude with unvulcanized EPDM and perform vulcanization. An example of actual molding is given below. As the attachment shows, through co-extrusion a two-layered belt-shaped sample can be molded and used as a glass run channel. By enabling co-extrusion with unvulcanized EPDM and subsequent vulcanization, coating or other treatment is no longer needed and workability is improved. Additionally, as ultra-high molecular weight PE appears on the surface layer, the sliding properties and abrasion resistance of the glass run channel can also be improved.

Molding example and example of molding condition

Effects of LUBMER^™

Here the advantages gained when LUBMER^™ is actually used as a sliding material for glass run channels is shown. The following diagram shows slipperiness when an academic wave abrasion test is performed under dry and sand-less conditions. It is evident that the friction coefficient remains lower than with PU coating or PA flocking. These friction coefficient-reducing effects are similarly demonstrated under the presence of sand or water.

Improved process and work environment

By enabling co-extrusion with unvulcanized EPDM and subsequent vulcanization, LUBMER^™ also removes the need for coatings or other treatment and improves workability. The following diagram shows the work processes for various EPDM surface sliding property modification methods. Even when compared with nylon flocking or urethane coating, the number of tasks can be significantly reduced, and no volatile organic compounds (VOCs) are produced during the work process.

Summary

Using LUBMER^™ on the sliding layer of glass run channels can improve GRC's sliding properties and durability. Additionally, adopting co-extrusion can reduce the number of work processes previously required, contributing to improved costs and a better working environment.